By the JP-Z-Eisei Kagaku 29(6), 418-22, it is known to vaporize, for determining mercury in organic samples, the mercury by heating the samples. The mercury is passed through a washing solution and is accumulated as gold amalgam. Then, the gold amalgam is heated and the mercury is set free. The obtained mercury vapor is optically measured. Similar methods for measuring the concentration of mercury in rocks is described in GB-Z "Analyst" (London) 102 (1214), 399-403, and in "Analytica Chimica Acta" 78(2), 479-82.
German Published Patent Application No. 3,641,386 describes a method of automatically generating gaseous or vaporous samples from a liquid for atomic absorption spectroscopy. When carrying out this method, a protective gas is passed over the liquid and, then, a reagent is added to the liquid for forming gaseous or vaporous sample substances. The thus formed sample substances are passed to a trap or a measuring device by means of the protective gas. According to the teaching of German Published Patent Application No. 3,641,386, the entire protective gas is directly passed into the liquid after the reagent addition. Also, different reagents can be consecutively added to the liquid. It is intended to thereby enable faster and more reliable, fully automatic analysis because the protective gas which passes through the liquid has a stirring action. Sample receptacles are successively conveyed to a work station. Thereat, an outlet member is set upon the sample receptacle which is open at the top, by means of a mechanism. This outlet member guides various tubes which are introduced into the sample and contains an outlet communicating with the space above the sample liquid. German Published Patent Application No. 2,748,685 likewise describes an apparatus for producing a gaseous measuring sample from a sample liquid and for passing such measuring sample into a measuring cuvette of an atomic absorption spectrometer by means of a protective gas. Also therein, the sample is arranged on a stepwisely advancing conveyor device. Connections for infeeding and outfeeding the protective gas and for metering the reagent are provided in a connecting member which is vertically movable and can be set upon the sample receptacle by means of a servo motor.
German Published Patent Application No. 2,737,727 describes an apparatus for determining elements in gaseous, solid or liquid samples by using "forward scattering". A measuring light beam having the resonance wavelength of a desired element is passed through a measuring cuvette. A polarizer is arranged in front of the measuring cuvette and an analyzer is located in the rear of the measuring cuvette and arranged crosswise relative to the polarizer. A magnetic field acts upon the measuring cuvette so that the atoms present in the measuring cuvette are subject to the Zeeman effect. The measuring cuvette is connected to a furnace which is closed and contains a crucible holding the sample to be analyzed. By means of a suction device, sample vapor is drawn from the furnace through the measuring cuvette. Due to the interaction with the resonance line components obtained as a result of the Zeeman effect, there is produced a rotation of the polarization plane which is dependent upon the concentration of the desired element and whereby, despite the crosswise arrangement of the polarizer and the analyzer, a light flux passes through the arrangement and which light flux is dependent upon the concentration of the desired element and impinges upon a photoelectric detector.
U.S. Pat. No. 4,023,929 relates to a method of determining the mercury content of water. The water is collected in collecting means, evaporated at 1000.degree. C., and decomposed in a pyrolysis zone at temperatures between 1000.degree. C. and 1200.degree. C. During this operation, mercury vapor is driven passed over a metal surface by means of a carrier gas. The mercury is enriched at the metal surface. The enriched mercury can be driven off again from the adsorbing metal surface by heating and can be measured.
U.S. Pat. No. 4,758,519 describes a method of continuously analyzing gaseous mercury in a gas containing a mercury compound. During this process, the gas is treated with a reducing agent prior to the measurement in order to reduce the mercury compound present in the gas to metallic mercury.
A publication by Mertens and Althaus, entitled "Determination of Mercury with the Aid of the Amalgam Technique Using Hydroxylammonium Chloride and Sodium Borohydride or Tin(II) Chloride", published in "Fresenius Zeitschrift fur analytische Chemie" 1983, vol. 316, pages 696 to 698, describes an apparatus for determining mercury by feeding reagents to a reaction vessel. The thus formed mercury vapor is passed by a nitrogen stream through a wash flash and a drying device and past a gold-platinum net. The mercury is bound thereat as an amalgam and thereby enriched. The gold-platinum net is heated by heating means and the enriched mercury is driven off. The thus recovered mercury vapor is passed into the measuring cuvette of an atomic absorption spectrometer by means of an inert carrier gas like nitrogen. German Published Patent Application No. 3,044,627 relates to an apparatus for introducing a sample into a graphite tube for flameless atomic absorption spectroscopy. A sample is applied to a sample carrier which can be introduced into a crucible shape and is heated by means of a heating device in a contactless manner. The heating device may be formed, for example, as a lamp, the radiation of which is concentrated at the sample by means of a concave mirror. Drying and ashing of the sample thus can be effected outside of the graphite tube. German Patent No. 3,204,584 is concerned with an apparatus for storing a multitude of liquids to be delivered in an automatic chemical analyzer. A movable holder receives a multiple number of closable liquid vessels. This holder conjointly with the liquid vessels is arranged within a chamber. The liquid vessels are individually conveyed to a suction position by means of the holder. An associated closure is provided for each one of the liquid vessels. The closure is opened at the suction position by means of a closure actuating device. A small tube for liquid withdrawal is then introduced into the liquid vessel through an opening in the chamber.
German Patent No. 2,954,181 relates to a sample feeder for automatically feeding a sample from above into a sample infeed opening provided in a furnace for flameless atomic absorption spectroscopy. Sample receptacles are movable into take-up positions by means of a turntable. In the take-up positions, a take-up tube is introduced into the sample receptacle. The sample is taken up and metered into the sample infeed opening of the furnace.